Tubs, spas or showers generally have a number of fluid flow ports or nozzles. Each flow port usually transmits or jets water or a water-air froth into the tub, spa or shower. Enhanced treatment or enjoyment for a user typically results from increased control over the flow of fluid to the tub, spa or shower.
One design employs a multi-ported valve having a handle to allow a user to rotate an inner cylindrical member relative to an outer cylindrical casing for selective alignment of ports of the inner cylindrical member and ports of the outer cylindrical member, for selective flow among a water supply and recirculating system, a spa, and a swimming pool. For instance, the user can manually rotate the handle to align a first port for flow of water to the spa and a second port for flow of water from the spa, and then the user can further manually rotate the handle to stop the flow of water to move from the spa and instead align the first port for flow of water to the swimming pool and align the second port for flow of water from the swimming pool. These first and second ports are the only ports for water flow between the valve and the spa for between the valve and the swimming pool. For example, the manual rotation of the handle by the user does not allow selection among individual ones, sets, or subsets of ports for water flow into the spa. Such a design is disclosed in U.S. Pat. No. 3,874,413 issued to Valdez.
Another configuration includes an air valve for spas and baths. Air is drawn from the air valve to a jet by a venturi effect created by coupling of a water pump to the jet. A knob is manipulated by a user to selectively cause full, partial, or no air flow from the air valve to the jet. The air valve includes a housing having a port and a slot, and a barrel having a port. A user can turn the knob connected with the barrel, to cause selective flow or blockage of air, by selectively aligning the port of the barrel with the slot or port of the housing, or by selectively blocking the port of the barrel by aligning neither the slot nor port of the housing with the port of the barrel. In this configuration, only one jet delivers water from the pump to the spa or bath. The manual turning of the knob by the user does not allow selection among individual ones, sets, or subsets of ports for water flow into the spa or bath. The manipulation of the knob simply selects the quantity of air content in the flow through the jet. Such a configuration is disclosed in U.S. Pat. No. 4,918,768 issued to DeSousa et al.
Another aspect of such systems results from the pressurized water and air utilized to provide a therapeutic effect to a user. The pressurized water and/or air may result in “hammering” or pressure buildup in such devices which may result in damage thereto. One method of preventing damage due to such pressure buildup is to provide for a pressure relief valve which may allow water and/or air to escape from such a system when pressure in the system rises above an acceptable level.
Thus, a need exists for increasing selectability and/or controllability of water delivery to a tub, spa or shower while reducing the likelihood that pressure build-up will cause damage to such a system.